By using operant conditioning procedures of proven utility in behavioral pharmacology, the proposed research will attempt to increase the "resolving power" of these methods by concurrently measuring peak force, duration, and interresponse time of individual responses. These dependent variables will be used to study the effects of selected neuroleptics and other drugs upon behavior maintained by some simple schedules of positive reinforcement, and by additional methods which permit measurement of discriminative motor control in rats. More specifically, the motor features of operant responses will be used to characterize the varying degrees of extrapyramidal effects produced by antischizophrenic drugs such as haloperidol and clozapine. Many of the motor effects observed consequent to the use of major tranquilizers develop after chronic use. Therefore, in addition to assessing acute drug effects, some of the proposed experiments include evaluation of selected neuroleptics over several weeks, with continued monitoring of specific motor features of behavior (peak force, steadiness of limb control, etc.) for weeks after discontinuing drug treatment. The experiments using simple schedules of reinforcement should provide new information about the manner in which schedules of reinforcement, force of response, and rate of response determine drug effects on behavior. In the proposed research rats will be reinforced for paw-pressing an isometric force transducer. Analog voltages from the transducer will be dignitized by a laboratory computer system which will take the response measurements and compute response consequences. The computer system is currently operational.